Spark-plug.



J. J. PLATT.

Patented Ma 1917.

2SHEETS- ET 7.

J; J. PLATT.

SPARK PLUG. APPUCATION H LED OCT. 3. I914.

Patented May 29 2 SHEETS-SNEET 2.

JOHN JELIJIFF PLA'IT, 0F MILFORD, CONNECTICUT.

SPARK-PLUG.

Specification of Letters Patent.

Patented May 29; 1 917.

Application filed October 3, 1914. Serial No. 864,883.

To all whom it may con cm:

Be it known that l, Joux Jenurr PLA'I'J, a citizen of the United States. residing at Milford, in the county of New Haven and State of (.onnecticut. ha ve in vented new and useful Improvements in Spark-Plugs, of which the following is a specifiratimn This invention rt lates to spark plugs, the broad object of the invention being to produce a reliable and economically manufactured combined self-cleaning and priming spark plug.

h'iorc specifically slated, the object of the present invention is to produce a plug embodying a plurality of electrodes one of which is tubular and communicates with the exterior of the plug upon the outside of the internal combustion engine; the bore of said tube containin a stem which is movable therein and which provides for opening said bore to'admit of the passage of priming liquid and air therethrough for a purposewhich will appear.

With the above and other objects in view, the invention consists in the novel construction, combination and arrangement of parts. as herein described, illustrated and claimed.

In-the accompanying drawingsz- Figure 1 is a side elevation of a sparle plug embodying the present invention.

Fig. 2 is a diametrical longitudinal section through the same.

Fig. 3 is a detail view of the valve and stem.

Fig. 4 is a view of the latter.

Fig. 5 is an inner end view of the tubular electrode.

Fig. 6 is an inner end view of the complete plug showing the truss bar.

Fig. 7 is a fragmentary sectional view of a plug showing a removable stem.

Fig. S-is a detail view of the removable stem of Fig. 7.

Referring to the drawings 1 designates the body or shell of the improved spark plug which is threaded at 2 to adapt the same to be screwed into an engine and threaded at 3 to receive the not 4 by means of which the porcelain and'other parts of the plug are clamped'in fixed relation to the main body or shell 1.

The body or shell 1 is also provided with thensual not face 5 to be used in conjunction with the nut 4 for the purpose stated.

Within the body or sh'ell l is what is usually known as. porcelain indicated at 6, the

same forming an insulating holder for one of the electrodes. This porcelain is provided with a flange 7 of larger diameter than the remainder of the porcelain to provide for clamping the porcelain in place within the shell 1 which is recessed as shown at 8 to receive the flange 7. At its inner end the porcelain is recessed at 9 to receive the enlarged lower end of the tubular electrode hereinafter particularly described while the outer end of the porcelain is tapered or frusto-conical as shown at 10.

The tubular electrode indicated at 11 is bored throughout its entire length aud the inner end thereof is enlarged as shown at 12 and received in the recess 9 of the porcelain 6. The electrode-11 is also provided with a flange 13 which fits intoa correouter extremityof the.

sponding recess 1-4 in the porcelain as shown ;in Fig. 2. At its outer end theelect'rode 11 .is threaded at 15 to receive a combined nut and contact disk 16 which bears against the rcelain 6: On the threaded portion 15 o the tubular-electrode-11, a priming cup 17 is threaded as shown in Fig.- 2 and the priming cup itself is externally threaded at 13 to receive a contact nut'19, the usual wire from the magneto or battery being clampedbetween the parts 16 and 19 so as to place the tubular electrode in circuit.

In the preferred embodiment of this invention, in connection ,withthetubular electrode 11, I employ n valve stem 20 at the inner end of which is a conical valve 21 which controls the inner end of the bore of the tubular electrode 11. The stern20 extends entirely through the tubular electrode and is sufficiently long to also extendthroughthe 'cup 17 and beyond the. same where it is threaded at 22 to receive an insulated thumh piece or cap 23 by means of which the valve 21 may be unseated. The cap 23 has an in- I sulating lining 24 to prevent a shock from being impartedto the operator when he pushes the stem inwardly to unseat the valve by placing his hand or linger on the mp 23. 25 designates a valve closing spring which encircles the stem 20 within the cup 17. At its inner endthe main body or shell 1 is provided with a truss bar 2" for supporting the other electrode 27. 'l'his'electrode is shown as having a conical face which normally lies close to the adjacent rod of the enlarged portion 12 of the tubular electrode 11 as shown in Fig. l The electrode 27 is threaded as shown at '28 and passes through a nutfl29 shown in the form of a disk internal I y threaded to engage the threads 28 of the electrode 27, the central portion of the truss 5 bar 26 being formed with a slot or recess 30 in which the nut 29 is received and from which it isprevented from escaping by said electrode '27. By simply turning the nut 30, the electrode 27 may be fed toward and away from the other electrode 11 to obtain the requisite distance between the two electrodes for obtaining the necessary length of spark.

The stem 20 is provided with air and liquid passages which, in the preferred embodiment of the invention, are shown as formed by providing the stem 20 with oppositely located flat faces 31, one of these fiat. faces forming a'passage for air while the other forms a passage for liquid such as gasolene or other priming liquid. Within the enlarged portion '12 of the electrode 11, grooves 32 are provided to allow for the entrance 0f the priming'liquid and the escape of air, carbon or other impurities blown off from the cylinder of the engine through'the spark plug. I

Another form of the invention is illustrated'in Figs. 7 and 8 in which the stem indicated' at 33 is made removable from the'tu',' bular electrode 11', said stem being enlarged and threaded at 34 so that it may be screwed into the priming cup 17 which is shown as internally threaded at 35 for that purpose. The stem 33 is also provided at its extremity with a milled thum piece or cap 36 to facilitate unscrewing the stem and withdrawing and replacing the same; In the construction just referred to, the stem is withdrawn from the tubular electrode which permits riming liquid to be poured into the cup 1 "from whence it is carried through the spark plu into the engine. It also enables the sparE to be observed through the bore of the tubular electrode.

Under ordinary conditions the bore of the also permitting cleaning or .decarbonizing liquid to be introduced therein. sTllG opening also permits carbon to be-blown out through the plug, in the usual carbon cleaning process. It will be observed that the working parts referred to are contained within the plug and t erefore protected from inju the device 0 this invention being there ore self-contained. When the valve is pushed inwardly it comes in contact with the opposing electrode and prevents any 5 ark. The construction is also extreme y simple and the plug as a whole may' therefore be manufactured at small cost.

\Vhat I claim is 1. A self cleaning and priming spark plug, comprising in combination, an outer shell, a truss bar at the ignition end of said shell, an electrode carried by said. truss bar, a. tubular electrode extending centrally and longitudinall 'of the shell, and having its inner end en arged to form an expanded tubular end portion which is oounterbored to form an internal beveled valve seat, a stem extending within and lengthwise of said tubular electrode, and a valve on said stem having a beveled face to engage said valve seat, said stem having oppositely disposed flat faces which rovide separate and inde pendent exterior ongitudinal air and liquid 30 P s ag 2. A self cleaning and priming spark plug, comprising in combination, an outer she I, a truss bar at the i ition end of said shell, an electrode carrie by said truss bar, a tubular electrode extending centrally and longitudinally of the shell, a stem extending within and lengthwise of said tubular electrode, a valve on said stem controlling the bore of said tubular electrode, a priming cup threaded directly on the outer end of said tubular electrode, and a contact nut threaded directly on a reduced part of said cup.

In testimony whereof ture in presence of two witnesses.

JOHN J ELLIFF PLATT.

lVitnesses:

FREDERICK J. Pm'rr, CL'n-ronn II. Im'rr.

I affix my signa 9 5 

